This invention relates to an image pickup apparatus or actuator device capable of automatically tracking an object, i.e., the so-called robot eye.
The construction of a known image pickup apparatus using a gimbal is shown in FIG. 7. A sensing optical system and an image pickup device such as CCDs are contained in a generally cylindrical image pickup unit 100. The image pickup apparatus is connected with a control unit 130 via a cable K1. The image pickup unit 100 is supported on a rotary frame 102 by a shaft 101, and is rotatable about a Y-axis. The rotary frame 102 is supported on a fixed frame 104 by a shaft 103, and is rotatable about an X-axis. The X-axis is substantially horizontal and stationary. On the other hand, the Y-axis moves on a plane perpendicular to the X-axis.
A gear 112 is secured to the shaft 101 and engaged with a gear 111 which is fixed on a drive shaft of a motor. 113. A Y-axis moving mechanism 110 is constructed by the gears 111, 112, the motor 113, and an encoder (not shown), and adapted for controlling the rotation amount and the rotation direction of the shaft 101. The motor 113 and the encoder are connected with the control unit 130 via a cable K2.
Likewise, a gear 122 is secured to the shaft 103 and engaged with a gear 121 secured to a drive shaft of a motor 123. An X-axis moving mechanism 120 is constructed by the gears 121, 122, the motor 123, and an encoder (not shown), and adapted for controlling the rotation amount and the rotation direction of the shaft 131. The motor 123 and the encoder are connected with the control unit 130 via a cable K3.
In automatically tracking an object, the control unit 130, processes an image picked up by the image pickup unit 100, and separatingly extracts an image of the object. The control unit 130 calculates a necessary movement amount to move the image of the object to the center of a screen. Further, the control unit 130 drives the motor 113 and 123 based on a calculation result to orient the optical axis of the sensing optical system of the image pickup unit 100 toward the object.
In the construction of the conventional image pickup apparatus, at least the Y-axis moving mechanism 110 needs to be provided integrally with the rotary frame 102 or inside the image pickup unit 100. Accordingly, the X-axis moving mechanism 120 has to drive not only the image pickup unit 100 and the rotary frame 102, but also the Y-axis moving mechanism 110 together. This causes the problem that the X-axis moving mechanism 120 is subject to a larger load in comparison with the Y-axis moving mechanism 110.
Further, the space for the cables K1, K2 to connect the movable elements such as the image pickup unit 100 and the Y-axis moving mechanism 110 with the control unit 130 are required, consequently making it difficult to render the apparatus smaller and lighter.
Furthermore, in order to accomplish the dust-, humidity- and water-preventing purposes, it is necessary to contain the entire apparatus including not only the image pickup unit 100 but also the Y-axis moving mechanism 110 and the X-axis moving mechanism 120 in a special housing, making the construction of the apparatus disadvantageously more complicated and larger.